Multi-directional key switch assembly

Abstract

A multi-directional key switch assembly comprises first stage switches and second stage switches of different kinds disposed alternately arrayed at 45° on a common circle at angular intervals on a printed-circuit board, a truncated semi-spherical shell shaped rolling member disposed on the board in overlying relation to thee switches, slide members disposed on the undersurface of the semi-spherical shell shaped rolling member in opposition to the corresponding first stage switches, and actuating means disposed in correspondence with the second stage switches. A key top is mounted on the rolling member and has an integral operating stick extending from the undersurface thereof. The operating stick is inserted in a receiving bore formed through the rolling member from the upper surface to the undersurface thereof along the central axis thereof. Rolling the rolling member by pressing on the key top will cause the corresponding first stage switch to be turned ON, and further continued rolling of the rolling member will actuate the corresponding second switch to turn it ON.

What is claimed is: 
     
       1. A multi-directional key switch assembly capable of selectively actuating a plurality of switches, said assembly comprising: a substrate board having disposed thereon first fixed contacts and second fixed contacts for a plurality of first stage switches and a plurality of second stage switches of a different kind, and having a different type of actuation than that of said first stage switches, said first fixed contacts and second fixed contacts being alternately arrayed on a common circle;   first and second roof portions disposed over the first and second fixed contacts, each of said first and second roof portions having a circumference elastically supported on said substrate board;   first and second movable contacts attached to undersides of said first and second roof portions in opposition to said corresponding first and second fixed contacts and being cooperative with the first and second fixed contacts to define said first stage and second stage switches, respectively;   a rolling means having first and second actuating means disposed in overlying relation to said first and second movable contacts, respectively, said first and second actuating means being operative in response to external forces applied in a desired direction about the center of said common circle to actuate corresponding one or more of said first stage and second stage switches; and   a key top mounted on said rolling means and adapted in response to external forces applied to said key top to roll said rolling means, whereby rolling said rolling means in any desired direction will cause the corresponding first stage switch or switches to be turned ON, and further continued rolling of said rolling means in the same direction will actuate the corresponding second switch or switches to turn it or them ON;   said first actuating means including slide members disposed over said first movable roof portions, respectively, slide member receiving bores formed in said rolling member for receiving the slide members slidably in a direction parallel to a central axis of said rolling means, and stroke producing springs for imparting, to the corresponding slide members, a biasing force to push the slide members against said first movable roof portions away from said slide member receiving bores; and   said second actuating means including engaging protrusions protruding from said rolling member for actuating said second movable roof portions.   
     
     
       2. The multi-directional key switch assembly of claim 1 further including a central fixed contact disposed on said board means in the center of said common circle, and a central movable contact disposed in opposition to said central fixed contact, wherein said rolling means has a receiving bore extending therethrough along the central axis thereof, and said key top has an operating stick extending from the undersurface thereof through said receiving bore and adapted to actuate said central movable contact and/or roll said rolling means. 
     
     
       3. The multi-directional key switch assembly of claim 2 further including a key top biasing spring disposed between said key top and said rolling means for imparting a biasing force to urge said key top away from said rolling means, said key top having extending downwardly from the undersurface thereof at least one integral engagement piece which is in engagement with an engagement hole formed in said rolling means to prevent dislodgement of the key top from said receiving bore. 
     
     
       4. The multi-directional key switch assembly of claim 3, wherein said rolling means includes a generally truncated semi-spherical shell shaped rolling member having a generally truncated semi-spherical outer peripheral surface, and a housing accommodating said rolling member and having a generally truncated semi-spherical inner slide wall surface slidably contacting said generally truncated semi-spherical outer peripheral surface of the rolling member, said housing having an opening in its top end to expose the top surface of said rolling member to the exterior, said key top protruding from said opening. 
     
     
       5. The multi-directional key switch assembly of claim 4, wherein each of said fixed contacts comprises a pair of interdigiting comb-like electrodes. 
     
     
       6. The multi-directional key switch assembly of claim 4, wherein said substrate board includes a printed-circuit board having formed thereon said first and second fixed contacts, and a rubber resilient sheet overlying the upper surface of said printed-circuit board, said rubber resilient sheet being formed on its undersurface with recesses corresponding to said respective fixed contacts, those portions of said rubber resilient sheet forming the upper walls of said recesses constituting movable roof portions on the undersurfaces of which said corresponding movable contacts are formed, said rolling means being disposed above said rubber resilient sheet. 
     
     
       7. The multi-directional key switch assembly of claim 6, wherein said generally truncated semi-spherical shell shaped rolling member has an integral cylindrical sleeve portion extending downwardly from the undersurface thereof, said receiving bore for receiving said operating stick being formed through said cylindrical sleeve portion, and there is provided a rolling member biasing spring disposed between the undersurface of said rolling member around said cylindrical sleeve portion and said rubber resilient sheet for imparting a biasing force to always urge said rolling member into contact with said housing. 
     
     
       8. The multi-directional key switch assembly of claim 7, wherein the biasing force of said rolling member biasing spring is greater than the biasing force of said key top biasing spring. 
     
     
       9. The multi-directional key switch assembly of claim 4, wherein said slide members each comprise an engagement portion engageable in the corresponding slide member receiving bore to prevent dislodgement of the slide member from the receiving bore. 
     
     
       10. The multi-directional key switch assembly of claim 4, further including a rubber resilient sheet having formed integrally therewith frusto-conical domes for enclosing the respective second fixed contacts, said domes each having a thickened movable roof portion surrounded by a thinned peripheral wall, said second movable roof portions of said domes having corresponding said second movable contacts formed in the undersurfaces thereof, said second actuating means being adapted to press down on the upper surfaces of the movable roof portions of said domes. 
     
     
       11. The multi-directional key switch assembly of claim 4, wherein a tilt angle θ 2  required of the operating stick to turn ON each of said second stage switches is greater than a tilt angle θ 1  required of the operating stick to turn On each of said first stage switches. 
     
     
       12. The multi-directional key switch assembly of claim 4, wherein four each of said first and second fixed contacts are provided and arrayed on said common circle at equal angular intervals. 
     
     
       13. The multi-directional key switch assembly of claim 4, wherein said central fixed contact comprises a C-shaped outer electrode and a circular electrode disposed within said outer electrode. 
     
     
       14. The multi-directional key switch assembly of claim 13, wherein said central movable contact is a snap plate formed of a thin resilient metallic material having an upwardly convex spherical surface and resting on said C-shaped outer electrode.